Paper sizing



2,995,483 PAPER SIZING Francis A. Bonzagni, Springfield, Mass, assignor to Monsanto Chemical Company, St. Louis, Mo., acorporation of Delaware No Drawing. Filed Dec. 13, 1957, Ser. No. 702,500

6 Claims. (Cl. 162- 480) This invention relates to the preparation of improved resins suitable for use in paper sizes, and particularly'to resins of the type prepared from reaction products .of

rosin and an organic compound of acidic character con-:

taining a CO-C='C' group, which reaction products are known as fortified rosins, and to the use of the saponified product of these improved fortified rosins (i.e., a fortified rosin size) in the engine sizing of paper.

A simple flow diagram of the preparation and use of the improved fortified rosin-s is as follows:

Organic compound '7 I having a O-O=C group Rosin Heated above 1 140 C.

Fortified rosin Sized paper 1 The preparation and use of fortified rosins of this general type in paper sizes are known. However, certain difiiculties have been encountered with the use of the saponified product of these rosins in paper sizing, including excessive foamformation and a tendency toward flotation of the pulp in the heaters and in subsequent operations, as in the refiners, pumps, agitators and screens.

I Patented Aug. 8, 196l- Although the amount offoam and float which occurs in the beater sizing of paper with saponified rosin may be sufi'lcient to somewhat disrupt the sizing operation, it is also known that heretofore, when using a saponified fortified rosin, the tendency of such fortified rosin cause foam and float is increased.

. Itg'ha's now been found that, by removing rosin oils present in rosin used to prepare rosin sizes, the foam and float of a fortified rosin size of the type described can be so markedly reduced as to virtually eliminate the problem.

In general, the objects .of this invention can be accomplished by reacting rosin and an organic compound of acidic character containing a CO--C=C- group under conditions of time, temperature and pressure at which substantially no decarboxylation takes place and all, or substantially all, the rosin oils are removed. The resulting fortifiedrosins are exceedingly useful,'when saponified, in the sizing of paper, as they are free of detrimental rosin oils and,.,,at the same time, retain their original sizing'efficiency. Rosins suitable for the purpose of this invention include gum rosin and wood rosin. Examples of suitable organic compounds of acidic character containing a --CO-'-'C=C group include alpha, beta-unsaturated polybasic organic "acids or acid anhyrides, such as maleic, citraconic and fumaric acid, or maleic, citraconic and itaconic anhydride.

It is known, for example, that one method of separating turpentine from'gum resin is by steam stripping. This operation, however, is performed at lower temperatures (of the order of about 160 C.) than those contemplated by this invention and, as a result, rosin'oils remain which contribute to'high foam and float.

In the preparation of the resinous reaction products of this invention, it is usually preferable to first carry out the reaction between the rosin and the organic compound of acidic character containing a CO-'C=C group, as this reaction will. take place at temperatures below the temperature suitable for removing the float-producing It is accordingly a primary object of the present invention to produce rosins of the type described which, when saponified and employed in the engine sizing of paper pulp, utilizing sizing methods known to the art, do not cause appreciable foam formation and at the same time markedly reduce the tendency of the pulp solids to reduced to a minimum without attendant loss of sizing efliciency of the fortified rosin size.

Stillfurther objects and advantages of the invention will appear from the following description and appended claims.

oils. -This order is not essential, however, as the resin oils can be removed prior to reacting the rosin with said compound containing the CQ-C=C- group. Thus, said reaction can be performed at temperatures as low as about C. but preferably at or above the melting point of the rosin. Although not absolutely necessary, it is usually preferable to remove the rosin oils at reduced presures, such as 15 to 200 of Hg, as this permits completion of the removal of the oils in shorter periods of time than otherwise, and also permits removal of the rosin oils at lower temperatures, thus avoiding excessivedecarboxylation. When operating at such-reduced pressures, the best results are obtained by heating the reaction mixture at temperatures between about'220 and 230 C. for about one hour. However, good results can be obtained under these conditions for longer or shorter periods varying from one-half totwo hours. In,

addition, it has been found that at temperatures of about 220 to 230, C., pressures of 30 to 40 mm. of Hg are quitesatisfactory. The removalof the float-producing oils does not seem to occur, within a practical length-of time, below about C. However, temperatures as low as 190 C. can be used, but in such case, four-to five hours may be required for complete removal of the rosin oils, as well as the use of low pressures, no higher than about 15 mm. of Hg. v

Conversely, although temperaturesjas high as 240 C. can be employed,'the reaction timemust then be shortened somewhat, for example, to about 15 minutes, in order to avoid excessive decarboxylation. tures of 260 C. or higher can be used; however, in such case, the sojourn time at such temperature must be very short.

The rosin oils can also be removed by steam distilla Tempera-- I paste size containing about 70% solids.

rosins, thereby producing a substantially rosin oil-free rosin or fortified rosin. Thus, it is seen that the invention lies in the discovery that by removing rosin oils under conditions of time, temperature and pressure as to avoid substantial decarboxylation, a fortified rosin size can be prepared from gum'rosin, wood rosin or tall oil rosin, which fortified rosin is used to produce a size having superior qualities of low foam and float.

Many techniques have been used in the laboratory to study the foaming tendency in sizes. Most of such techniques have been based on foam or froth formation, and the results have often been misleading. Large voluminous bubbles are not harmful, it is the small, opaque dense bubbles that cause the trouble. The test which is used to determine float, which has been proven to correlate with mill experience, is briefly as follows:

Standard bleached-sulfite pulp is beaten to a predetermined freeness, diluted to a standard consistency, and aerated byan electric mixture. Size and later' alum are added at exact times. .After aeration, the slurry is transferred to a graduate. The number of cc. of clear water under the floating pulp after 16 hours is a quantitative measure of the tendency of that size to cause air stabilization (and thus produce float);-. The value is called an air stabilization factor, or A.S.F.

A guide to A.S.F. values is given below:

' A further understanding of the invention will be obtained from the following examples:

Example 1 Fifteen hundred grams of molten gum rosin and 42 grams of maleic anhydride were charged to a suitable reaction vessel. The mixture was then heated to about 220 C. and held at that temperature for about 15" minutes. The acid number of the mixture was then determined and sufficient 50% sodium hydroxide was added to result in a size having an acid number of 22, with the further addition of sufiicient water to give a The float of the size thus prepared was determined to correspond to an A.S.F. value of about 100. This example demonstrates the undesirable high float of fortified rosin sizes prepared according to an established practice of the 811.

Example 2 Fifteen hundred grams of molten gum rosin and 42 grams of maleic anhydride were charged to a suitable reaction vessel. The mixture was heated to 220 C. with stirring and was then vacuum distilled for 70 minutes at .a pressure of 30 to 50 mm. of Hg.

Example 3 Ten hundred and twelve grams of molten gum rosin and 30 grams of fumaric acid were charged to a suitable reaction vessel. The mixture was heated to 192 C. and was then steam distilled for about two hours, with the temperature gradually increasing to about 255 C.

The rosin obtained in the above reaction was dissolved in 320 grams of water with the aid of 174 grams of 50% caustic soda, which'resulted in a 70% solution of neutralized product suitable for use in the engine sizing of paper. The float of this material was equivalent to an A.S.F. number of about 6.

Example 4 'Eleven hundred and sixty-six grams of molten gum rosin and 50 grams of fumaric acid were charged to a suitable reaction vessel. The mixture was eventually heated to a temperature of 276 C., the time of heating from 200 to 276 taking about one hour. g

The rosin obtained in the above reaction was .dissolved in 371 grams of water with the aid of 278 grams of 50% caustic soda, which resulted in a 70% solution of neutralized product suitable for use in the engine sizing of paper. The float of this material was equivalent to an A.S.F. number of about 12.

Example, 5

A fortified wood rosin size, prepared essentially like the fortified'gum rosin size of Example 1, was determined to have a float corresponding to an A.S.F. value of 94. This example demonstrates the undesirable high float for fortified rosin sizes prepared according to an established practice of the art.

Example 6 40 mm. of Hg absolute.

'Ihe rosin obtained above, 360' grams of 50% sodium hydroxide and 354 grams of water were mixed together in a suitable vessel, thereby effecting saponification, which resulted in a 70% solution of neutralized rosin product suitable for use in the engine sizing of paper. The float of the product was found to correspond to an A.S.F. value of 1.

Example 7 The distillate from Example 3 was collected and the rosin oils separated from the condensed steam. To portionspf the size prepared in Example 3, varying amounts of the distilled rosin oils were-then added and a float determination made. The results were as follows:

Weight percent oils added: Float I 0.5 6 1.0 26

Example 8 .A paper pulp beater was charged with unbleached sulfite pulp suspension containing about 2% of dry pulp. To the charge was added a dispersion of rosin oil-free fortified rosin size prepared in Example 2 in an amount equal to about 2% of fortified rosin based on the weight of dry pulp. The dispersion was beaten into the pulp for about 15 minutes, after which aluminum sulfate, in

an amount equal to about 3% based on the weight of the'dr'y pulp, was added. After beating the above for rosin sizes prepared by the method herein described have a sizing efiiciency equal to the sizing efliciency of forti fied rosin sizes prepared by methods of the prior art.

In the above examples, the organic compound of acidic character containing a'-CO-C=C group is used in the ratio of 2.8 parts by weight per 100 parts by weight of'rosin. However, the advantages of the invention are equally applicable to reaction products containing lower or higher. proportions of such compounds; for example, as high as l'part per 3 parts of rosin.

In order to obtain satisfactory results in using the resinous reactionproducts of this invention, it is impor-- tant that substantially all of the rosin oil be removed from the reaction mixture. In order to determine when substantially all of the float-producing oils have been removed, a sample of fortified rosin is removed from the distillation vessel after about one hour from 'the start of the distillation, saponified, and a float determination is made. If the float has reached a satisfactory minimum,- distillation is discontinued and, conversely, if the float is still too high, distillation is continued for a short period of time and another float' determination is then made. Because of the wide range of concentration of rosin oils which rosins contain, due to such factors as geographic -origin of the rosin, the season of the year when the rosin was collected, method of producing the crude rosin, 'etc., the time for continuing the distillation cannot be exactly defined but nevertheless will be obvious to those skilled in the art when employing the method of the invention to remove float-producing rosin oils without attendant decarboxylation.

From the above examples, it is seen that the removal of rosin oils by the method of this invention results in a fortified rosin size having superior qualities of very low foam and float. While either atmospheric or sub-atmospheric distillation (i.e., distillation .under apressure less than atmospheric or a distillation wherein the partial pressure of the rosin oils is below what their partial pressure would be for an atmospheric distillation) is satisfactory for removing the rosin oils, in the case of tall oil rosin, sub-atmospheric distillation with steam has been found to give the greatest reduction of float when said rosin is to be employed in the engine sizing of paper.

This application is a continuation-in-part of my earlier filed application, Serial Number 358,971, filed Iune l, 1953, and now abandoned.

What is claimed is:

1. In a process for sizing paper, the 'steps comprising incorporating into paper pulp an improved fortified rosin size comprising the saponified product prepared by the steps comprising (1) heating at temperatures above 140 C. from about one to about ten parts by weight of an organic compound of acidic character containing a --CO-C=C- group, with 100 parts by weight of rosin 6 140 C. from about one to about ten parts by weight of an organic compound of acidic character containing a COC=C group selected from the group consisting of maleic anhydride and fumaric acid, with 100 parts by. weight of rosin to form a fortified rosin, (2) heating said fortified rosin under reduced pressures to temperatures within the range of about 190 C. to about 260 C. and removing by distillation, float-producing rosin oils originally present in said rosin thereby producing a fortified rosin, substantially free of float-producing rosin oils, and (3) thereafter saponifying said fortified rosin by heating with an aqueous solution of caustic to form said fortified rosin size.

3. In a process for sizing paper, the steps comprising incorporating into paper pulp 'an improved fortified rosin size comprising the saponified product prepared by the steps comprising (1) heating at temperatures above 140 C. from about one to about ten parts by weight of an organic compound of acidic character containing a COC=C-- group selected from theg roup consist-i ing of maleic anhydride and fumaric acid, with 100 parts by weight of rosin to form a fortified rosin, (2) heating said fortified rosin to temperatures within the range of about 190 C. to about 260 C. while sparging said fortified rosin with steam to remove by steam distillation, floatproducing rosin oils originally present in said rosin, thereby producing a fortified rosin substantially free of float-producing rosin oils, and (3) thereafter saponifying said fortified rosin by heating with an aqueous solution of caustic to form said fortified rosin size.

4. In a process for sizing paper, the steps comprising incorporating into an aqueous suspension of paper pulp an improved fortified rosin size comprising the saponified product prepared by the steps comprising (1) heating at temperatures above 140 C. from about one to about ten parts by weight of an organic compound of acidic character containing a COO=C group selected from the group consisting of maleic anhydride and fumaric acid, with 100 parts by weight of rosin to form a fortified rosin, ('2) heating said fortified rosin to conditions of temperature and pressure whereby float-producing rosin oils in said fortified rosin are removed by distillation, thereby producing a fortified rosin substantially free of float-producing rosin oils, and (3) thereafter saponifying said fortified rosin by heating with an aqueous solution of alkali to form said fortified rosin size.

5. In a process for sizing paper, the steps comprising incorporating into an aqueous suspension of paper pulp an improved fortified rosin size comprising the saponified product prepared by the steps comprising (1) heating at temperatures above 140 C. from about one to about ten parts by weight of maleic anhydride with 100. parts by weight of rosin to form a fortified rosin, (2) heating said to form a fortified rosin, (2) heating said fortified rosin fortified rosin to temperatures within the range of about 190 C. to about 260 C. while sparging said fortified rosin with steam to remove by steam distillation, floatproducing" rosin oils originally present in said rosin, thereby producing a fortified rosin substantially free of float-producing-'rosin oils, and (3) thereafter saponifying said fortified rosin by heating with an aqueous solution of sodium hydroxide to form said-fortified rosin size.

6. In a process for sizing paper, the steps comprising incorporating into an aqueous suspension of paper pulp an improved fortified rosin size comprising the saponified product prepared by the steps comprising (1) heating at temperatures above C. from about one to about ten parts by weight of fumaric acid with 100 parts by weight of rosin to form a fortified rosin, (2) heating said fortified rosin to temperatures within the range about C. to about 260 C. while sparging said fortified rosin with steam to remove by steam distillation, float-producing rosin oils originally present in said rosin, thereby producing a fortified rosin substantially free of float-producing rosin oils, and (3) thereafter saponifying said fortified rosin by heating with an aqueous solution of sodium"hydroxide to 2,299,312 Drishfield Oct. 20, 1942 form said fortified rosin size. ,309,346 Landes et al. Jan. 26, 1943 2,538,103 Koonce et al. Jan. 16, 1951 References Cited in the file of this patent 2,628,918 Wilson et a1 Feb. 17, 1953 UNIT T 6 2,684,300 Wilson et a1. July 20, 1954 ED STATES PA i 26 1931 I 2,771,464 Hastings et a1. Nov. 20, 1956 1,807,483 Lgan aY 2,930,106 Wrotnowski Mar,29,1960

2,121,294 Humphrey June 21, 1938 UNITED STATES PATENT. @FFICE q; T1 {GATE Q EQTIN Patemt, No, 2 995 d83 August 8 1961 Francis A Bonzagni It is hereby certified that error appears in the above numbered pat- ,ent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 68, for "371 read 495 3 same line 68, for "278" read 335 column 4- line 32 for "for", read of column 6 line 20 for theg Pomp read the group a Signed and sealed this 9th day of i962a cfsis m Attest:

ERNEST Wu SWIDE R J; i DAVID L. LADD Attesting Officer I Commissioner of Patents 

1. IN A PROCESS FOR SIZING PAPER, THE STEPS COMPRISING INCORPORATING INTO PAPER PULP AN IMPROVED FORTIFIED ROSIN SIZE COMPRISING THE SAPONIFIED PRODUCT PREPARED BY THE STEPS COMPRISING (1) HEATING AT TEMPERATURES ABOVE 140* C. FROM ABOUT ONE TO ABOUT TEN PARTS BY WEIGHT OF AN ORGANIC COMPOUND OF ACIDIC CHARACTER CONTAINING A -CO-C=C- GROUP, WITH 100 PARTS BY WEIGHT OF ROSIN TC FORM A FORTIFIED ROSIN, (2) HEATING SAID FORTIFIED ROSIN TO TEMPERATURES WITHIN THE RANGE OF ABOUT 190*C. TO ABOUT 260*C. AND REMOVING BY DISTILLATION, FLOAT-PRODUCING ROSIN OILS ORIGINALLY PRESENT IN SAID ROSIN, THEREBY PRODUCING A FORTIFIED ROSIN SUBSTANTIALLY FREE OF FLOAT-PRODUCING ROSIN OILS, AND (3) THEREAFTER SAPONIFYING SAID FORTIFIED ROSIN BY HEATING WITH AN AQUEOUS SOLUTION OF ALKALI TO FORM SAID FORTIFIED ROSIN SIZE. 